The first term is a quadratic in \(\mathbf {P}^e\)  and can be expressed as \(\operatorname{Tr}{\mathbf {P}^e}^T \mathbf {V} \mathbf {P}^e\) , where \(\mathbf {V}\)  has \(v_{ij} = -w_{ij}\)  and \(v_{ii} = \sum w_{ij}\)  [1]}.
The second term is a constant, say \(k\) , and the third term can be bounded as follows:
